Used with
permission of Maiken Naylor, University at Buffalo, Buffalo, NY, USA,
http://ublib.buffalo.edu/libraries/units/sel/exhibits/stamps
A well-known theorem in geometry is named after Pythagoras, who flourished in the 6th century BC, and was a teacher in Samos, Babylon, and Egypt: the sum of the squares of the sides of a right triangle equals the square of the hypotenuse. Actually, the so-called Pythagorean triples were known already in Babylonian times. The striking design of the Greek stamp is a visual representation of the theorem.